Which Blood for Checking Glucose

The blood that we need to use to check our blood glucose levels may seem obvious. After all, it’s a check, not a test to pass or fail. We need to use our own blood, not blood borrowed from a friend or foe.

But until now some basic questions about blood glucose testing haven’t had a tested answer. They do now with the publication of a study in this month’s issue of Diabetes Care, a professional journal of the American Diabetes Association.

The abstract of the study, “Self-Monitoring of Blood Glucose: The Use of the First or the Second Drop of Blood” is free online. My friend Dr. Bill Quick, who also writes about diabetes for HealthCentral, sent me the full text of the study.

The seven Dutch diabetes professionals who researched basic questions about blood glucose testing recruited 123 people with diabetes. They checked the variability of their blood glucose testing results in four different situations:

1. When they did or did not wash their hands

2. After they handled fruit (specifically apples or bananas)

3. After washing their fingers that had touched the fruit

4. And two different amounts of pressure applied to their fingers — squeezing

Their conclusions were simple and straightforward. But now for the first time we have them based on the actual experience of real people who have diabetes:

1. We don’t have to waste a drop of blood to use a second drop — but only if we wash our hands first.

2. But when we aren’t in a position to wash our hands and they aren’t particularly dirty or exposed to something that has sugar in it, testing with a second drop of blood will work.

3. Which finger we use doesn’t matter.

4. When we apply heavy pressure — meaning squeezing a lot — we can get unreliable results.

“The first choice is to wash the hands with soap and water, dry them, and use the first drop of blood,” the authors wrote. “Firm squeezing of the finger should be avoided.” The authors admitted that they had a hard time defining the difference between firm and light squeezing.

Strangely, the study did not look at the old recommendation that we should use alcohol to clean our fingers. Maybe they read my review of the Clever Chek meter, which I wrote here in November 2007. I hope that I disposed of the myth that it’s better not to use alcohol.

“The [Clever Chek] packaging includes a box of ‘Alcohol Prep Pads,’” I wrote then. But, “Any alcohol on the skin may interfere with your test result, so theexperts don’t recommend that you use alcohol prep pads routinely. Only where you don’t have warm water is it a good idea to use alcohol to clean the test area. And be sure to air dry it well before testing.”

Now, let’s all go and test our blood glucose with confidence that we know what we are doing.